This invention relates to a mechanism for multiplying rotary movement, and particularly to improvements in a valve assembly for the fill opening of a waste holding tank in the sanitary system of a recreational vehicle (RV).
Removable waste holding tanks adapted for use with toilets are typically positioned within an interior compartment of the RV. Waste is transported by the toilet structure to the holding tank where it is stored. The holding tank can be conveniently removed from the RV through an exterior access door and then transported to a waste disposal sight for emptying.
To enable the holding tank to accept waste products from the toilet of the sanitary system, a waste holding tank of the above mentioned type generally include a centrally disposed fill opening located within its top wall. A seal element surrounds the fill opening of the tank and includes an upper portion which seals against an outlet opening of the toilet bowl. So constructed, waste can be easily and sanitarily transferred into the holding tank.
To prevent the holding tank from leaking waste when it is removed from the RV and transported to the disposal site, it is necessary to provide a mechanism for securely closing the fill opening. Normally, a movable valve blade is mounted within the holding tank and is positioned to close off the fill opening. The valve blade may be actuated by an occupant of the RV to uncover the fill opening and thus enable the transferring of waste into the holding tank. The movable valve blade seals against a lower portion of the seal element thereby containing the waste within the holding tank and preventing odors from being vented into the RV.
An RV sanitary system incorporating the above structures is described within U.S. Pat. No. 4,908,885 and U.S. Pat. No. 4,776,631, both commonly assigned to the Assignee of the present application.
During actuation of the valve assembly, the valve blade is rotated or moved out of registry with the fill opening. The valve blade is coupled to an actuation arm which an operator of the assembly is required to rotate to open the valve assembly. The actual degree or amount of rotation required is determined by the width of the valve blade and the length of the actuation member. Generally, the shorter the length of the actuation member, the larger the required rotation. Because the valve blade most often requires operation in a restricted space, the length of the actuation arm is typically short and the degree of rotation is large.
When the holding tank is removed from the RV for emptying, the seal element and valve blade often become immersed in liquid waste and subjected to hydrostatic pressure. This often results in leakage problems. To prevent leaking, various seal elements for the fill opening have been developed to improve the tank's sealability.
The present invention is particularly directed to an improved inlet valve assembly which is not susceptible to the above leakage problems and which may be fully operated through a comparatively small rotation of the actuation arm.
Generally, the valve assembly includes a seal element and a valve blade which is actuated through two distinct movements. The first movement of the valve blade is substantially vertical and engages and disengages the valve blade with the seal element. The second movement is transverse or generally horizontal and moves the valve blade into and out of registry with the fill opening.
When opening a holding tank provided with the valve assembly of the present invention, the valve blade is first moved substantially vertically downward so as to disengage the seal element. The valve blade is then moved in a generally planar fashion out of registry with the fill opening thereby opening the holding tank. To achieve these two movements, the present invention uses two cooperating armatures which rotate about different centers of rotation. The armatures are coupled together in a novel fashion such that a rotation of one armature will produce a multiplied rotation in the other armature.
The seal element generally includes an annular lip which is oriented downwardly and inwardly of the fill opening and is adapted to engage the valve blade when the blade is in its closed position. The end of this lip is flanged and is doubled back or, in other words, is outwardly and downwardly flared. To ensure effective sealing of the fill opening, the flange of the seal element needs to be substantially vertically engaged by the valve blade. This prevents the flared end from moving out of its doubled back position.
Additional benefits and advantages of the present invention will become apparent to those skilled in the art to which this invention relates from the subsequent description of the preferred embodiment and the appended claims, taken in conjunction with the accompanying drawings.